How to Maintain Legionella Pneumophila Viability During Sampling and Detection?
Legionella pneumophila is an aquatic bacterium found in natural and man-made water systems, capable of causing severe pneumonia. For water and biofilm sampling, maintaining bacterial viability and nucleic acid stability during collection and transport is crucial. Italian health authorities recommend using osmotic solutions like saline for sampling and transport media. However, these solutions cannot neutralize antimicrobial substances present in the environment.
Can SRK Medium Neutralize Antimicrobials and Maintain Bacterial Viability?
Researchers evaluated the ability of the liquid SRK medium to maintain L. pneumophila viability and nucleic acid stability at different concentrations and temperatures. They prepared bacterial suspensions at approximate concentrations of 10^4, 10^3, and 10^2 CFU/mL and performed culture and real-time PCR analyses at 0, 24, 48, and 72 hours under room temperature (20-25°C) and refrigerated (2-8°C) conditions.
How Did SRK Perform at Room Temperature?
The results showed that SRK medium supported L. pneumophila growth well at room temperature, with a 75-95% recovery rate after 48 hours. Real-time PCR detection also confirmed good DNA stability for up to 48 hours.
And at Refrigerated Temperatures?
Under refrigerated conditions (2-8°C), SRK medium exhibited superior preservation effects. The bacterial recovery rate was 83-100% after 72 hours, and real-time PCR detection showed nucleic acid stability for at least 72 hours.
What Molecular Detection Methods Were Used?
The researchers used two commercial real-time PCR detection kits: iQ-Check from Bio-Rad and qualyfast from Bioside. Both methods accurately quantified L. pneumophila, consistent with culture results.
What Are the Practical Applications of SRK Medium?
This study confirmed the excellent performance of SRK medium in maintaining L. pneumophila viability and nucleic acid stability. SRK medium could be used for water and biofilm sample collection and transport, potentially standardizing environmental monitoring procedures for Legionella and contributing to the prevention of Legionnaires' disease outbreaks.
Therefore…
The liquid SRK medium has demonstrated promising applications as a sampling and transport medium for environmental L. pneumophila samples. It efficiently preserves bacterial viability and nucleic acid stability while being highly compatible with real-time PCR molecular detection methods, providing reliable technical support for Legionella risk assessment.
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References
Evaluation of an Environmental Transport Medium for Legionella pneumophila Recovery
